The major objectives of the project are the elucidation of the mechanism by which insulin, catecholamines, thyroid hormones, glucocorticoids and growth hormone regluate the metabolism of isolated rat fat cells. Emphasis is placed on the role cyclic AMP-independent mechanisms in the regulation of lipid mobilization from adipose tissue. Four specific areas being intensively are: 1. Adenosine regulation of hormone-stimulated fat cell syslic AMP metabolism and lipolysis. 2. Thyroid hormone regulation of catecholamine action in fat cells. 3. Alpha-adrenergic agents activation of phosphatidylinositol turnover and the relationship of this to entry of calcium. 4. Role of phospholipase A2 activation in hormonal regulation of lipolysis.